In plasma-based systems, plasma is generated within a plasma chamber. For example, a radio frequency (RF) generator supplies power to a plasma chamber. When a gas is supplied to the plasma chamber in addition to the power, plasma is struck within the plasma chamber. The plasma may be used for numerous processes, e.g., etching, depositing, cleaning, chemical deposition, etc.
Plasma chambers are different even under manufacturing control. Some minor differences between the plasma chambers, e.g., parts of the plasma chambers, cable routing within the plasma chambers, losses along RF transmission lines of plasma systems that include the plasma chambers, etc., may create enough difference between the chambers to induce variation in one or more of the processes. For example, a 1 to 2 percent variation in an etch rate is created due to the differences in the plasma chambers.
Also, a plasma chamber changes over time. For example, characteristics of a plasma chamber change with wear and tear of the plasma chamber, condition of walls of the plasma chamber, and/or erosion of parts of the plasma chamber.
It is in this context that embodiments described in the present disclosure arise.